Lubricant cartridge for wheel end assemblies

ABSTRACT

A wheel end assembly of a heavy-duty vehicle includes a pair of bearings mounted on an axle spindle, and a wheel hub rotatably mounted on the bearings so that the bearings, the axle spindle, and the wheel hub generally define a cavity in the wheel end assembly. The wheel hub is formed with a port that communicates with the cavity and atmosphere. A lubricant cartridge includes a generally rigid body defining a chamber for containing a predetermined amount of semi-fluid grease. The cartridge also includes a generally rigid nozzle that is connected to the body and is in fluid communication with the chamber. The nozzle defines an opening and is formed with features for removably connecting the cartridge to the wheel hub port. Semi-fluid grease is urged from the cartridge chamber through the nozzle, through the port, and into the cavity to lubricate the wheel end assembly.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/833,685, which was filed on Jul. 27, 2006.

BACKGROUND OF THE INVENTION

1. Technical Field

The invention relates to the lubrication of vehicle wheel end assemblies, and in particular to the lubrication of wheel end assemblies of heavy-duty vehicles, such as tractor-trailers. More particularly, the invention is directed to a cartridge containing a predetermined amount of semi-fluid grease for lubricating a wheel end assembly of a heavy-duty vehicle, in which the cartridge includes a nozzle adapted for securely connecting to a lubricant port formed in a wheel hub of the wheel end assembly.

2. Background Art

For many years, the heavy-duty vehicle industry has utilized wheel end assemblies which typically are mounted on each end of one or more axles. Each wheel end assembly typically includes a hub rotatably mounted on a bearing assembly, which includes an inboard bearing and an outboard bearing, which are in turn immovably mounted on the outboard end of the axle, commonly known as an axle spindle. As is well known to those skilled in the art, for normal operation of the wheel end assembly to occur, the bearing assembly and surrounding components must be lubricated with oil or grease. Therefore, the wheel end assembly must be sealed to prevent leakage of the lubricant, and also to prevent contaminants from entering the assembly, both of which could be detrimental to its performance. More specifically, a hubcap is mounted on an outboard end of the wheel hub, and a main seal is rotatably mounted on an inboard end of the hub and the bearing assembly in abutment with the axle spindle, resulting in a closed or sealed wheel end assembly.

On wheel end assemblies that are mounted on non-drive axles, such as those found on the trailer axles of a tractor-trailer, it is desirable to retain a predetermined amount of lubricant in each wheel end assembly, which increases the life of the bearing assembly, in turn reducing the cost of maintaining and/or replacing the bearing assembly. Historically, oil has been used as the lubricant for the bearing assemblies, but it may not be the optimum lubricant for achieving the goal of increased bearing assembly life. More particularly, if the main seal on the wheel end assembly degrades, there is a tendency for the oil to leak out of the assembly due to its relatively low viscosity in comparison to other lubricants. When the oil leaks out, the bearing assembly may become under-lubricated, which reduces its life. In addition, in the event of such an oil leak, the main seal usually must be repaired or replaced. Moreover, when the oil leaks out of the wheel end assembly, it may leak onto components of an associated brake system, such as the brake shoes, which must then be repaired, thereby increasing the cost associated with an oil leak. Such potential disadvantages associated with oil leaks have led to increasing use of semi-fluid grease as an alternative to oil as a lubricant for bearing assemblies in wheel end assemblies on non-drive axles.

The higher viscosity of semi-fluid grease causes it to flow less readily than oil, which is an advantage in reducing potential leaks, but creates the need for alternative methods of filling the wheel end assembly with lubricant. That is, with oil, a hole typically is provided in the hubcap, enabling the oil to be poured into the sealed wheel end assembly through the hubcap according to methods that are known in the art. However, semi-fluid grease does not readily flow to both the inboard and outboard bearings and the hub area proximate the bearings using such a hubcap fill hole. Thus, the grease must be pumped or dispensed into the area of the bearing assembly, which has led to the development of various methods in the prior art for filling the wheel end assembly with the proper amount of semi-fluid grease. In any method of filling the wheel end assembly with semi-fluid grease, metering of the grease to inject the proper amount is an important consideration, since the addition of too much lubricant may create excessive pressure within the wheel end assembly and cause the main seal to leak, while the addition of too little lubricant may lead to inadequate lubrication of the bearing assembly and thus reduce its life.

One known prior art method for filling a wheel end assembly with semi-fluid grease, which method typically is used during initial assembly of the wheel end assembly, involves mounting only the inboard bearing of the bearing assembly on the axle spindle prior to adding the grease to the wheel hub. In this prior art method, the inboard bearing is mounted on the axle spindle, and the wheel hub is mounted on the inboard bearing without the outboard bearing and without a retaining nut, the latter of which typically is used to secure the position of the bearings and the hub on the axle spindle. A nozzle typically is inserted in the gap between the axle spindle and the hub, and a pre-measured amount of semi-fluid grease is dispensed through the nozzle into the gap against the inboard bearing. Once the grease has been added, the outboard bearing is mounted on the axle spindle and the retaining nut is installed and tightened onto the axle spindle.

This prior art method includes a distinct disadvantage, since the lack of the installation of the outboard bearing during grease introduction requires that an operator maintain a relatively horizontal position of the wheel hub to prevent damaging the main seal of the wheel end assembly. That is, without the outboard bearing in place, there is a tendency for the outboard end of the wheel hub to drop down onto the axle spindle, which in turn can kink or damage the main seal at the inboard end of the wheel hub. In addition, while this prior art method may be employed somewhat efficiently during initial assembly of the wheel end assembly with factory-trained assemblers, it is much less practical for use in the field, such as during servicing of the wheel end assembly in a repair/maintenance facility, since the wheel end assembly would have to be at least partially disassembled just to add lubricant. As is well-known in the art, it is desirable for lubrication of a wheel end assembly in the field to be performed with minimal disassembly.

Another method, which may be used during initial assembly and in the field, involves using a wheel hub that includes a fill port that is formed in the wheel hub. The fill port communicates with a cavity between the inboard and outboard bearings, and a pre-measured amount of semi-fluid grease is dispensed into the wheel end assembly through the port. In the prior art, radially-oriented ports were drilled and tapped through the wall of the wheel hub between the inboard and outboard bearings, but such radially-oriented ports included certain disadvantages, such as increased manufacturing costs and an inability to be used on thin-walled wheel hubs. These disadvantages led to the development of a novel axially-oriented fill port that is formed in an existing hubcap bolt hole of the wheel hub, and which is more fully described in a separate application being filed concurrently herewith by the assignee of the present invention, Hendrickson USA, L.L.C. Such use of fill ports in wheel hubs has enabled easier filling of wheel end assemblies with semi-fluid grease during initial installation and in the field, but certain disadvantages remain.

For example, to fill a wheel end assembly in the field, the person servicing the assembly must check the manufacturer's specifications for the proper amount of semi-fluid grease to be added, then measure that amount and introduce it into the assembly through the fill port. This procedure requires significant time and effort, and as a result, may not be adequately performed in some cases. That is, the person servicing the assembly may not accurately measure the amount of grease to be added. Such inaccuracy could lead to the addition of too much or too little grease, which are both undesirable, as described above.

Therefore, a need has existed in the art to develop a delivery system for semi-fluid grease having a predetermined amount of grease for use in the field, and which may also find application during initial assembly. One such system has been developed in the prior art, consisting of a flexible plastic bag filled with a predetermined amount of semi-fluid grease and a flexible tube, which is inserted into the fill port formed in the wheel hub. However, the flexible bag exhibits certain disadvantages. More particularly, since the bag is flexible, it may easily slip from a user's hands during the filling operation, the chances of which are increased in the field, since the user's hands may be dirty and thus slippery from working with components that have gathered dirt and grime from over-the-road travel. In addition, since the bag is flexible, the bag itself must be squeezed to introduce the semi-fluid grease into the wheel end assembly, and the user may not be able to squeeze substantially all of the premeasured semi-fluid grease out of the bag. Moreover, the flexible tube that is inserted into the wheel hub fill port does not provide a secure connection to the wheel hub and/or may slip out of the fill port during the filling operation, in either case possibly resulting in spillage or loss of grease intended for introduction into the wheel end assembly.

The above-described disadvantages of prior art delivery systems for filling wheel end assemblies of heavy-duty vehicles with semi-fluid grease in the field, and at times during initial assembly, have created a need in the art for a lubricant cartridge containing a predetermined amount of semi-fluid grease, which is easy to handle and efficiently dispenses the grease, and which provides a secure connection to a fill port formed in a hub of the wheel end assembly to minimize or eliminate loss of grease intended for lubrication of the assembly. The present invention satisfies this need.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a lubricant cartridge for delivering semi-fluid grease to a wheel end assembly of a heavy-duty vehicle that contains a predetermined amount of grease.

Another objective of the present invention is to provide a lubricant cartridge for delivering semi-fluid grease to a wheel end assembly of a heavy-duty vehicle that is easy to handle and efficiently dispenses the grease.

Yet another objective of the present invention is to provide a lubricant cartridge for delivering semi-fluid grease to a wheel end assembly of a heavy-duty vehicle that is capable of securely connecting to a fill port formed in a wheel hub of the wheel end assembly, so that spillage or loss of lubricant during the fill operation is minimized or eliminated.

These objectives and others are obtained by the lubricant cartridge for a wheel end assembly of a heavy-duty vehicle of the present invention. In an exemplary embodiment of the invention, the wheel end assembly includes a pair of bearings mounted on an axle spindle and a wheel hub rotatably mounted on the bearings. The bearings, wheel hub and axle spindle define a cavity in the wheel end assembly. The wheel hub is formed with a port that is in communication with the cavity and atmosphere. The lubricant cartridge includes a generally rigid body that defines a chamber for containing a predetermined amount of semi-fluid grease, and a generally rigid nozzle connected to the body. The nozzle includes a first end that is in fluid communication with the chamber and a second end that defines an opening, and the nozzle is formed with features proximate the second end for removably securing the nozzle to the port. Semi-fluid grease contained in the body chamber is selectively urged from the body chamber, through the nozzle, through the port, and into the cavity to lubricate the wheel end assembly.

These objectives and others are also obtained by the method for filling a wheel end assembly of a heavy-duty vehicle with lubricant using a lubricant cartridge of the present invention. In an exemplary embodiment, the method includes providing a wheel end assembly. The wheel end assembly includes a pair of bearings mounted on an axle spindle and a wheel hub rotatably mounted on the bearings. The bearings, wheel hub and axle spindle define a cavity in the wheel end assembly. The wheel hub is formed with a port that is in communication with the cavity and atmosphere. A lubricant cartridge is provided, and the lubricant cartridge includes a generally rigid body defining a chamber for holding a predetermined amount of semi-fluid grease, and a generally rigid nozzle connected to the body. The nozzle includes a first end which is in fluid communication with the chamber and a second end that defines an opening. The second end of the lubricant cartridge nozzle is removably connected to the wheel hub port, and semi-fluid grease is urged from the body chamber through the nozzle, through the port, and into the cavity. The lubricant cartridge nozzle is removed from the wheel hub port when the semi-fluid grease has been communicated from the cartridge to the cavity.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred embodiments of the present invention, illustrative of the best mode in which applicants have contemplated applying the principles, are set forth in the following description and are shown in the drawings, and are particularly and distinctly pointed out and set forth in the appended claims.

FIG. 1 is top perspective view of a flexible bag of the prior art for containing semi-fluid grease;

FIG. 2 is a top rear perspective view of the lubricant cartridge of the present invention;

FIG. 3 is a top outboard perspective view of an exemplary wheel hub of the type with which the lubricant cartridge of the present invention finds use;

FIG. 4. is a fragmentary longitudinal cross-sectional view of the wheel hub shown in FIG. 3 taken along line 4-4, shown incorporated into a wheel end assembly which is mounted on an axle spindle, and showing the lubricant cartridge of FIG. 2 securely connected to an axially-oriented fill port of the wheel hub; and

FIG. 5 is a fragmentary longitudinal cross-sectional view of a portion of another wheel hub, shown incorporated into a wheel end assembly which is mounted on an axle spindle, and showing the lubricant cartridge of FIG. 2 securely connected to a radially-oriented fill port of the wheel hub.

Similar numerals refer to similar parts throughout the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In order to better understand the lubricant cartridge of the present invention, a prior-art flexible bag for containing a predetermined amount of semi-fluid grease is shown in FIG. 1 and now will be described. Flexible bag 90 includes a body 92 in which semi-fluid grease is contained. A flexible tube 94 extends from body 92 and includes a distal end 96. Bag 90 is formed of a flexible plastic material. In operation, distal end 96 of tube 94 is trimmed so that an opening (not shown) is formed in the distal end, thus enabling semi-fluid grease in bag 90 to flow from the bag when the bag is squeezed. More specifically, after the trimming step, a user holds body 92, inserts flexible tube 94 in a fill port of a wheel hub, such as fill port 49 formed in wheel hub 42 (FIG. 5), and squeezes the body to force grease out of the opening of distal end 96 of bag 90 and into a cavity 36 (FIG. 5) formed in the wheel hub.

As described above, while flexible bag 90 includes a predetermined amount of semi-fluid grease, it has certain disadvantages, such as the potential to easily slip from a user's hands due to its flexible nature, especially if the user's hands are dirty and/or slippery; the need to be squeezed about body 92 to force the semi-fluid grease out of the bag; and a lack of a secure connection with fill port 49, which may allow the semi-fluid grease to spill and thereby defeat the goal of using a container with a predetermined amount of lubricant. Such disadvantages have created a need in the art for a lubricant cartridge that contains a predetermined amount of semi-fluid grease, which is easy for a user to handle and efficiently dispenses the grease, and which provides a secure connection to a fill port formed in a wheel hub of a wheel end assembly. The present invention satisfies these needs, as will now be described.

Turning now to FIG. 2, a lubricant cartridge of the present invention is indicated at 210. Lubricant cartridge 210 preferably includes a generally rigid cylindrical body 212, having a first end 214 and a second end 216, and forming an internal chamber 228 (FIG. 4) for containing semi-fluid grease. Preferred body 212 is formed of a cardboard or other paper-based material that is configured in a cylindrical shape, and has an internal lining to resist leaching of the semi-fluid grease through the cardboard. Optionally, cylindrical body 212 may be formed of a generally rigid plastic material, in which case an internal lining may not be necessary, since the plastic may resist leaching of the grease. Cylindrical body 212 is sized to be received by and held in a standard caulking gun (not shown). A predetermined amount of semi-fluid grease is contained in chamber 228, and is dispensed from the chamber when the caulking gun is operated and thus causes an end cap 218 disposed in body 212 proximate first end 214 to move toward second end 216, as will be described below.

A nozzle 220 extends from second end 216 of body 212, and is in fluid communication with chamber 228 to enable semi-fluid grease to be dispensed from the chamber through the nozzle. Nozzle 220 preferably is formed of a plastic or other generally rigid material, and includes a distal end 222 that is capable of being opened by a user and thus is in selective communication with atmosphere. More particularly, distal end 222 of nozzle 220 may be formed with an opening 232 (FIG. 4) that receives a removable plug 226 (FIG. 2), and which is inserted in the nozzle opening when cartridge 210 is not in use, thereby preventing inadvertent escape of semi-fluid grease from the cartridge. Alternatively, distal end 222 may be formed with a closed tip, which is then cut or trimmed by a user to form opening 232 when it is desired to use lubricant cartridge 210. Between second end 216 of body 212 and nozzle distal end 222, nozzle 220 includes a tapered portion 230. In accordance with an important feature of the present invention, between tapered portion 230 and distal end 222, threads 224 preferably are formed on the outer surface of nozzle 220, as will be described in greater detail below.

With reference now to FIG. 4, when it is desired to fill a wheel end assembly with a proper amount of semi-fluid grease, lubricant cartridge 210 is connected to a fill port 121 formed in a wheel hub 118 of a wheel end assembly 102. More particularly, in order to understand the environment in which lubricant cartridge 210 is used, wheel end assembly 102, which is assembled on an axle spindle 100, now will be described. Axle 10 depends from and extends transversely across the trailer of a heavy-duty tractor-trailer (not shown). A typical heavy-duty tractor-trailer includes one or more non-drive axles 10 suspended from the trailer, with each of the axles having a wheel end assembly 102 mounted on each end of the axle. For the sake of clarity, only one axle end and wheel end assembly 102 will be described herein. Axle 10 includes a central tube 14, and axle spindle 100 is integrally connected by any suitable means, such as welding, to each end of the central tube. Axle central tube 14 generally is tubular-shaped and is formed with an internal cavity 18. Axle spindle 100 is formed with an internal cavity 101.

Wheel end assembly 102 includes a bearing assembly having an inboard bearing 104 and an outboard bearing 106 that are immovably mounted on the outboard end of axle spindle 100. More particularly, inboard bearing 104 is mounted on the outer diameter of axle spindle 100 and its inboard surface is in abutment with a shoulder 108 formed on the axle spindle. Outboard bearing 106 is mounted on the outer diameter of axle spindle 100 near the outboard end of the axle spindle.

Wheel hub 118 is rotatably mounted on inboard and outboard bearings 104, 106 in a manner well known to those skilled in the art. A cavity 116 is defined in wheel hub 118 between inboard and outboard bearings 104, 106, and axle spindle 100. A bearing spacer (not shown) optionally is disposed between bearings 104, 106 in cavity 116 to conveniently maintain proper spacing between the bearings. A nut assembly (not shown) threadably engages the outboard end of axle spindle 100 and secures bearings 104, 106 and any bearing spacer in place.

Turning to FIG. 3, a hubcap (not shown) is mounted on the outboard end of hub 118 by a plurality of bolts that each pass through a respective one of a plurality of openings formed in the hubcap, and threadably engage a respective one of a plurality of aligned openings 124 formed in bosses 119 of the hub. Each opening 124 is formed with threads 123 to facilitate the threadable engagement of the hubcap bolts. In this manner, the hubcap closes the outboard end of wheel end assembly 102. As shown in FIG. 4, a main continuous seal 126 is rotatably mounted on the inboard end of wheel end assembly 102 and closes the inboard end of the assembly. More particularly, seal 126 is mounted on wheel end assembly 102 in a suitable manner and radially bridges hub 118 and axle spindle 100 to seal cavity 116. A plurality of interference-fit studs 128 are used to mount a brake drum, tire rim and tire (not shown) on wheel end assembly 102.

In order to maintain proper lubrication and operation of inboard and outboard bearings 104, 106, a suitable amount of semi-fluid grease lubricant is introduced into cavity 116 through fill port 121 formed in hub 118 using lubricant cartridge 210. More particularly, as shown in FIGS. 3 and 4 and more fully described in a separate application being filed concurrently herewith by the assignee of the present invention, Hendrickson USA, L.L.C., a selected one of hubcap bolt openings 124, that is, selected opening 124′, is drilled deeper inboardly than the other hubcap bolt openings and into cavity 116, to form axially-oriented fill port 121. Fill port 121 is tapped from its outboard end with threads 123′. Optionally, a visual indicator 129 is placed on the outer surface of hub 118 proximate selected opening 124′ in order to enable a user to determine which of hubcap openings 124 is the selected opening and thereby includes fill port 121.

With particular reference now to FIG. 4, to fill wheel end assembly 102 with lubricant, nozzle 220 of lubricant cartridge 210 is secured to axially-oriented fill port 121 formed in hub 118. More particularly, threads 224 formed on nozzle 220 mate with threads 123′ formed in fill port 121, enabling the nozzle to be threaded into the fill port once plug 226 (FIG. 2) is removed from the nozzle, or once nozzle distal end 222 is trimmed if the plug is not used. In this manner, lubricant cartridge 210 is securely inserted into and positively mechanically engages the outboard end of fill port 121, for a secure connection therewith. This threadable engagement of nozzle 220 with fill port 121 generally prevents leakage of grease from cartridge 210 or the wheel hub fill port during the fill operation.

As described above, body 212 of lubricant cartridge 210 is received by and held in a caulking gun. Once nozzle 220 is secured in fill port 121, the user squeezes the handle of the caulking gun in a manner well-known in the art, which causes the caulking gun to move end cap 218 (FIG. 2) from first end 214 of body 212 toward second end 216. Semi-fluid grease contained in body chamber 228 thus is forced from body 212, through nozzle 220, into fill port 121 and into hub cavity 116. The user continues to squeeze the handle of the caulking gun until end cap 218 is proximate second end 216 of body 212, that is, until cartridge chamber 228 is generally empty.

Preferably, the hubcap is not installed during the lubricant fill operation, which allows air within cavity 116 to escape as the semi-fluid grease is injected into the hub, thereby enabling the semi-fluid grease to flow relatively smoothly, providing an easy fill operation. After the semi-fluid grease lubricant is injected, nozzle 220 is removed from threads 123′ and a plug (not shown) is threadably engaged with the fill port threads until it bottoms out on the inboardmost threads of fill port 121 to seal cavity 116. Once the plug is in place, the hubcap is installed and the hubcap bolts are tightened in hubcap bolt openings 124 and selected opening 124′ formed in bosses 119 of hub 118, with the hubcap bolts threadably engaging threads 123, 123′ formed in the respective bolt openings.

Alternatively, the hubcap may be installed by inserting bolts in bolt openings 124 before filling wheel end assembly 102 with lubricant. More particularly, the bolts may be threaded into each respective non-selected opening 124, while selected opening 124′ remains open. Then, nozzle 220 of lubricant cartridge 210 is secured in selected opening 124′ and thus to fill port 121 via threadable engagement of nozzle threads 224 with fill port threads 123′, as described above. Semi-fluid grease is then introduced into fill port 121 and thus hub cavity 116 from lubricant cartridge 210 as described above. After the lubricant is injected, the plug is threadably engaged with threads 123′ formed in fill port 121 to seal the port and cavity 116. Once the plug is in place, the remaining hubcap bolt corresponding to selected opening 124′ is inserted and tightened in the selected opening.

The internal plug in fill port 121 seals the lubricant within cavity 116 and isolates it from the hubcap bolt, providing a redundant closure of the fill port to reduce the possibility of accidental loss of wheel end lubricant in the event of inadvertent loss of the hubcap bolt, due to an improper installation of the bolt or other event that could cause unintended removal of the bolt from opening 124′. Upon completion of the filling operation, lubricant cartridge 210 is removed from the caulking gun and discarded or recycled.

Depending on the application and/or the particular wheel end assembly involved, different premeasured amounts of semi-fluid grease may be needed. Therefore, different lubricant cartridges 210 may be designed to contain different premeasured amounts of semi-fluid grease. As is known in the art, the amount of grease contained within chamber 228 of each respective cartridge 210 preferably dictates the position of end cap 218, with the end cap being nearer to first end 214 of body 212 for larger amounts of grease, and farther away from the first end for smaller amounts. That is, end cap 218 can be infinitely adjusted to any position between first end 214 and second end 216 to selectively contain a desired amount of semi-fluid grease.

Turning now to FIG. 5, lubricant cartridge 210 of the present invention is shown in use for filling a second type of wheel end assembly and axle spindle end. More particularly, second wheel end assembly 12 includes a bearing assembly having an inboard bearing 22 and an outboard bearing 24 immovably mounted on the outboard end of an axle spindle 16. That is, inboard bearing 22 is mounted on the outer diameter of axle spindle 16 with its inboard surface in abutment with a shoulder 26 formed in the axle spindle. Outboard bearing 24 is mounted on axle spindle 16 near the outboard end of the axle spindle, and thereby includes a smaller inner diameter than inboard bearing 22 due to the taper of the axle spindle.

A cavity 36 is defined in wheel hub 42 between inboard and outboard bearings 22, 24, and axle spindle 16, and a correspondingly-tapered bearing spacer 28 optionally is disposed between the bearings in the cavity to conveniently maintain proper spacing between the bearings. A nut assembly, which includes an inboard nut 30, a lock washer 32, an outboard nut 34, and a set screw 35, threadably engages the outboard end of axle spindle 16 and secures bearings 22, 24 and bearing spacer 28 in place.

A wheel hub 42 is rotatably mounted on inboard and outboard bearings 22, 24 in a manner well known to those skilled in the art. A hubcap (not shown) is mounted on the outboard end of hub 42 by a plurality of bolts that each pass through a respective one of a plurality of openings formed in the hubcap, and threadably engage a respective one of a plurality of aligned threaded openings 44 formed in the hub. In this manner, the hubcap closes the outboard end of wheel end assembly 12. A main continuous seal 46 is rotatably mounted on the inboard end of wheel end assembly 12 and closes the inboard end of the assembly. More particularly, seal 46 is mounted on wheel end assembly 12 in a suitable manner and radially bridges hub 42 and axle spindle 16 to seal cavity 36. A plurality of interference-fit studs 48 (only one shown) are used to mount a brake drum, tire rim and tire (not shown) on wheel end assembly 12.

In order to maintain proper lubrication and operation of inboard and outboard bearings 22, 24, a suitable amount of semi-fluid grease is introduced into cavity 36. A radially-oriented fill port 49 is formed in hub 42 between inboard and outboard bearings 22, 24. To fill wheel end assembly 12 with lubricant, nozzle 220 of lubricant cartridge 210 is inserted into fill port 49. More particularly, port 49 may not contain threads that mate with threads 224 formed on nozzle 220. In such a case, second end 222 of nozzle 220 and threads 224 are of a diameter that is less than the diameter of fill port 49, but the maximum diameter of nozzle tapered portion 230 is greater than that of the fill port. In this manner, nozzle 220 is capable of being pressed by the user into port 49 until tapered portion 230 seats securely against the portion of the wall of hub 42 that forms the port, for a secure connection therewith. This mechanical engagement or force fit of nozzle 220 with fill port 49 generally prevents leakage of grease from cartridge 210 or the wheel hub fill port during the fill operation, when the nozzle is fully engaged with the fill port and the wall of hub 42.

As described above, body 212 of lubricant cartridge 210 is received by and held in a caulking gun. Once nozzle 220 is pressed into fill port 49, the user squeezes the handle of the caulking gun in a manner well-known in the art, which causes the caulking gun to move end cap 218 (FIG. 2) from first end 214 of body 212 toward second end 216. Semi-fluid grease contained in body chamber 228 thus is forced from body 212, through nozzle 220, into fill port 49 and into hub cavity 36. The user continues to squeeze the handle of the caulking gun until end cap 218 is proximate second end 216 of body 212, that is, until cartridge chamber 228 is generally empty. Once the proper amount of lubricant is inserted into cavity 36 by using lubricant cartridge 210, a plug (not shown) is inserted into port 49 and is secured in the port as known in the art. For example, the plug may include a pipe-style interfering thread, or may include a standard thread that compresses an O-ring, which seals port 49. Upon completion of the filling operation, lubricant cartridge 210 is removed from the caulking gun and discarded or recycled.

In this manner, lubricant cartridge 210 of the present invention provides an efficient, easy-to-use apparatus for filling wheel end assemblies 12, 102 with a predetermined proper amount of semi-fluid grease. More particularly, lubricant cartridge 210 is capable of providing a secure connection with wheel end assemblies 12, 102 having fill ports 49, 121, regardless of whether or not the fill ports are threaded to mate with cartridge nozzle 220, thereby generally preventing undesirable spillage of a pre-measured amount of grease. In addition, since lubricant cartridge 210 is received by a standard caulking gun, it is easy for a user to hold and operate, thereby reducing or eliminating the prior art problems of a flexible bag 90 that can easily slip from a user's hands, awkwardly requires the user to squeeze the semi-fluid grease out of the bag, and may allow spillage or loss of grease from the bag or wheel hub fill port. Moreover, lubricant cartridge 210 may be designed to accommodate different amounts of semi-fluid grease for easy and convenient use with different types of wheel end assemblies.

The present invention also includes a method for filling a wheel end assembly of a heavy-duty vehicle with lubricant using a lubricant cartridge containing a predetermined amount of semi-fluid grease, in which the cartridge includes a cylinder containing the grease and a nozzle that is capable of providing a secure connection to a lubricant port formed in a wheel hub of the wheel end assembly. The method includes steps in accordance with the description that is presented above and shown in FIGS. 2-5.

It is understood that the present invention finds application in the lubrication of all types of heavy-duty wheel end assemblies known to those skilled in the art, including other types of wheel end assemblies than those shown and described herein, and known to those skilled in the art, without affecting the concept or operation of the invention. For example, while the present invention has been described above with reference to wheel end assembles that are associated with non-drive axles, it is contemplated that the present invention may be used with wheel end assemblies that are associated with drive axles without affecting the overall concept or operation of the invention. In addition, the present invention may be used with all types of fill ports known in the art, including fill ports other than those shown and described above, regardless of location, orientation, and/or whether they include threads.

Moreover, types of mechanical engagement between the lubricant cartridge and wheel hub fill port other than threadable engagement or a force fit may be employed without affecting the overall concept or operation of the invention. For example, other means of providing a secure connection as known in the coupling art, such as a quick-connect assembly, may be used to connect the lubricant cartridge to the wheel hub fill port. Also, other types of containers for semi-fluid grease that are known in the art may be used in the present invention, such as refillable long-term use cartridges that provide for efficient dispensing of grease, and tubes or containers having a generally rigid body that is also substantially resilient, and having a relatively rigid nozzle. An example of a container having a generally rigid body that is also substantially resilient is a tube that is handled by a user without a caulking gun, and which maintains its shape until it is squeezed and thus deformed by a user, in contrast to prior art flexible bag 90, which generally lacks any rigid properties and typically does not maintain its shape without being supported.

Accordingly, the improved lubricant cartridge for wheel end assemblies of heavy-duty vehicles is simplified, provides an effective, safe, inexpensive, and efficient structure which achieves all the enumerated objectives, provides for eliminating difficulties encountered with prior art lubrication devices, and solves problems and obtains new results in the art.

In the foregoing description, certain terms have been used for brevity, clarity and understanding; but no unnecessary limitations are to be implied therefrom beyond the requirements of the prior art, because such terms are used for descriptive purposes and are intended to be broadly construed. Moreover, the present invention has been described with reference to exemplary embodiments. It shall be understood that this illustration is by way of example and not by way of limitation, as the scope of the invention is not limited to the exact details shown or described. Potential modifications and alterations will occur to others upon a reading and understanding of this disclosure, and it is understood that the invention includes all such modifications and alterations and equivalents thereof.

Having now described the features, discoveries and principles of the invention, the manner in which the lubricant cartridge is constructed, arranged and used, the characteristics of the construction and arrangement, and the advantageous, new and useful results obtained; the new and useful structures, devices, elements, arrangements, parts and combinations are set forth in the appended claims. 

1. A lubricant cartridge for a wheel end assembly of a heavy-duty vehicle, said wheel end assembly including a pair of bearings mounted on an axle spindle and a wheel hub rotatably mounted on said bearings, with the bearings, said wheel hub and said axle spindle defining a cavity in the wheel end assembly, the wheel hub being formed with a port, said port being in communication with said cavity and atmosphere, said cartridge comprising: a generally rigid body, said body defining a chamber for containing a predetermined amount of semi-fluid grease; and a generally rigid nozzle connected to said body, said nozzle including a first end in fluid communication with said chamber and a second end defining an opening, the nozzle being formed with features proximate said second end for removably securing said nozzle to said port, whereby semi-fluid grease contained in said body chamber is selectively urged from the body chamber, through the nozzle, through the port, and into said cavity to lubricate said wheel end assembly.
 2. The lubricant cartridge for a wheel end assembly of a heavy-duty vehicle of claim 1, wherein said features formed on said nozzle generally prevent leakage of semi-fluid grease during said urging of the semi-fluid grease into said wheel end assembly cavity when the features mechanically engage said port.
 3. The lubricant cartridge for a wheel end assembly of a heavy-duty vehicle of claim 2, wherein said port is tapped; and wherein said features include threads, whereby said nozzle threads engage said tapped port.
 4. The lubricant cartridge for a wheel end assembly of a heavy-duty vehicle of claim 2, wherein said features include a taper.
 5. The lubricant cartridge for a wheel end assembly of a heavy-duty vehicle of claim 1, wherein said lubricant cartridge is received by a caulking gun for urging said semi-fluid grease out of the cartridge.
 6. The lubricant cartridge for a wheel end assembly of a heavy-duty vehicle of claim 5, wherein said body is cylindrical.
 7. The lubricant cartridge for a wheel end assembly of a heavy-duty vehicle of claim 6, wherein said nozzle is disposed at a first end of said cylindrical body; wherein said body includes a cap generally disposed adjacent a second end of said body opposite said nozzle; and whereby said cap is urged toward said nozzle by said caulking gun to cause said semi-fluid grease to flow out of said cartridge body chamber.
 8. The lubricant cartridge for a wheel end assembly of a heavy-duty vehicle of claim 6, wherein said cylindrical body is formed of cardboard.
 9. The lubricant cartridge for a wheel end assembly of a heavy-duty vehicle of claim 6, wherein said cylindrical body is formed of plastic.
 10. The lubricant cartridge for a wheel end assembly of a heavy-duty vehicle of claim 1, wherein said nozzle opening receives a removable plug to seal said lubricant cartridge.
 11. A method for filling a wheel end assembly of a heavy-duty vehicle with lubricant using a lubricant cartridge, said method comprising the steps of: providing a wheel end assembly, said wheel end assembly including a pair of bearings mounted on an axle spindle and a wheel hub rotatably mounted on said bearings, the bearings, said wheel hub and said axle spindle defining a cavity in said wheel end assembly, the wheel hub being formed with a port, said port being in communication with said cavity and atmosphere; providing a lubricant cartridge, said lubricant cartridge including a generally rigid body defining a chamber for holding a predetermined amount of semi-fluid grease, and a generally rigid nozzle connected to said body, said rigid nozzle including a first end in fluid communication with said chamber and a second end defining an opening; removably connecting said second end of said lubricant cartridge nozzle to said wheel hub port; urging said semi-fluid grease from said body chamber through said nozzle, through said port, and into said cavity; and removing said lubricant cartridge nozzle from said wheel hub port when said semi-fluid grease has been communicated from said cartridge to said cavity.
 12. The method for filling a wheel end assembly of a heavy-duty vehicle with lubricant of claim 11, further comprising the step of providing a caulking gun for urging said semi-fluid grease from said body chamber.
 13. The method for filling a wheel end assembly of a heavy-duty vehicle with lubricant of claim 12, wherein said step of urging said semi-fluid grease from said body chamber through said nozzle includes using said caulking gun to cause a cap disposed adjacent an end of said body of said cartridge toward said nozzle.
 14. The method for filling a wheel end assembly of a heavy-duty vehicle with lubricant of claim 11, wherein said port is tapped, and said method further comprises the steps of: forming threads on said nozzle proximate said nozzle second end; and said step of removably connecting said lubricant cartridge nozzle to said wheel hub port includes threadably engaging said nozzle second end with said port.
 15. The method for filling a wheel end assembly of a heavy-duty vehicle with lubricant of claim 11, wherein said step of removably connecting said lubricant cartridge nozzle to said wheel hub port includes mechanically engaging a tapered portion of said nozzle with said port. 